Posted
by
Zonk
on Friday February 24, 2006 @10:15AM
from the kaboooooom dept.

starexplorer2001 writes "Space.com is reporting that NASA has detected a 'totally new' mystery explosion near our galaxy." From the article: "The event, detected Feb. 18, looks something like a gamma-ray burst (GRB), scientists said. But it is much closer--about 440 million light-years away--than others. And it lasted about 33 minutes. Most GRBs are billions of light-years away and last less than a second or just a few seconds."

Think of it this way - life appeared about a billion years ago, so that was twice as long ago as when this event happened. We're seeing an event that happenned a little before the dinosaurs appeared.

I think you're a bit off. Life appeared very soon after the Earth formed - a bit over four billion years ago. IIRC, multicellular life got going at about a billion years ago, and vertebrates invaded the land about half a billion years ago.

According to the Wilkinson Microwave Anisotropy Probe (WMAP) [nasa.gov], which, IIRC, is the most recent measuring of the Hubble Constant, the value for the Hubble Constant is 71 ± 4 km/s/Mpc. This would give the universe an age of 13.7 ± 0.2 billion years.

Other findings of WMAP include the makeup of the universe as 4% matter, 23% dark matter, and 73% dark energy, and a flat geometry for the universe.

Best estimates for the age of our solar system are currently about 4.6 billion years. Life ostensibly started very quickly, on a cosmological timeline. IIRC, earliest evidence of life points to around 3.5 billion years ago.

But your point about it being a lot more recent on a cosmological scale are correct.

2,586,000,000,000,000,000,000 miles away is 'nearby' ?!Was the origianl post. Then someone made a comment connecting lightyears to the age of the universe. That's a lot closer that 10 billion light years away, which is about the age of the universe

AFAIK the origal post was joking about it being close to us spacial not close to us in time. Besides I thought it was accepted pratice to refer to things we see now as happening now.

In astronomic dimensions, yes, that's not really far away....you're using a unit that doesn't lend itself well to the distances measured.

It's a hell of a lot of light years -- 440 million light years. If the universe is 17 billion years old, as it was last time I checked, that's about 2% of the radius of the universe, a respectable number. Or more locally, M31 in Andromeda is "only" 2.9 million light years away, so the "nearby" explosion is 150 times further than that.

It's just about 4400 times the diameter of our galaxy. So imagine the milky way were your house. Of course I don't know the diameter of your house, but let's just assume it's something like 10 meters. Then in relation it would be 44 km away. Ok, I admit, that's not really "nearby" any more... but then, thinking of it, the center of gravitation of a geek is his computer, so make that about half a meter, so the distance shrinks to 2.2 km... would you accept that as nearby, or do I have to mention that the r

It's also an interesting definition of "new." Since it happened 440 million light years away, and we're just detecting it now, it must have happened about 440 million years ago. Not exactly new, except in the network rerun "new to you" kind of way.

It's meaningless in imperial measurements. That'll be around 4,162,632,500,000,000,000,000 km.The Milky Way is around 946,052,840,000,000,000 km in diameter (our galaxy galaxy, not the candy bar, though I wish).That's 4,400 times the diameter of the galaxy;P Near?:D

I actually thought that the explosion of the Death Star, which occurred "A long time ago, in a galaxy far, far away" would have just about reached us by now. Watch for a second similar "mystery" explosion in about ten years.

Pessimist that I am, I figure we just witnessed the one other intelligent life form in the universe exterminating itself. Millennia from now when we confirm this, this event will be commemorated as We Are Alone Now Day.

If this makes no sense to you, then you have never lived or spent any significant amount of time in the Upper Peninsula of Michigan. You poor, poor troll [wikipedia.org]. Go home and kiss your children.

That's right: nothing can travel faster than the speed of light, not even information. We are witnessing something that happened millions of years ago, but because the electromagnetic waves (light, gamma rays etc) carrying the information are all travelling at the same speed (the speed of light), we get a chronological "look" at how the event panned out millions of years ago.

In actual fact, when you look at, say, a chair, you're actually seeing the chair as it was several (nano/pico/something, not sure of the exact time interval) seconds ago (a very small time period).

The indications are that when one particle is observed, the other entangled particle changes state immediately. Read "In Search of Schrodinger's Cat" for an example. There's other books, but that's the one that comes to mind immediately.

Right, but the result of the initial observation is still not deterministic, so you can't use non-locality to send information. At least according to the Copenhagen (most widely held) interpretation of QM.

Does that take into account the expansion of the universe? Is it 400 million light years away now or is that how far away it was when the exposion occurred (presumably it was closer 400 million years ago?)

Does that take into account the expansion of the universe? Is it 400 million light years away now or is that how far away it was when the exposion occurred (presumably it was closer 400 million years ago?)

Well, unfortunately, it's neither. "400 million light years" is close enough so that we can get away with this kind of approximation, but astronomers really don't talk about "distance" at scales much larger than this because it doesn't have much meaning. The "400 million" number was probably derived fr

As I understand it, astronomers use light-years-as-of-now to measure distance as that is the most relative to our frame of reference. I don't think they normally account for inflation. (There's a good economics pun in there somewhere but I'm too wired to make it out right now).

Technically you are correct. However, what most people mean is nothing can travel faster than the speed of light in a vaccuum.
Cherekov radiation is just an example of a particle traveling faster than the speed of light in air. While difficult, this is (obviously) not impossible. The speed of light varies depending on the medium it's traveling in, just like sound.
Now, if you accept the quantum mechanics view of the universe, theoretically some things can go faster than the spee

Now, IANAP, but I believe the deal with Cherenkov radiation is that it occurs when a charged particle (such as an electron) exceeds the speed of light in a medium. Since the propogation speed of light changes based on the medium through which it travels, in some media, this can be accomplished. The denser the material, the slower light propagates through it. Water is something like 0.75c. Diamond, I believe, is somewhere in the neighborhood of 0.4c. See Refractive Index [wikipedia.org] for more information.

In the case of Cherekov radiation the particles aren't traveling faster than C. The single particles phase velocity is traveling faster than the group velocity of the rest of the light. This causes the blue glow which is similar to an object breaking the sound barrier. But group velocity never exceeded C. Remember, light can slow down too.

As of "now" it is accepted that nothing travels faster than C.

Even this [iitk.ac.in] experiment did not conclude that the particle traveled faster than light. Only that the

It makes you realize just how fast multi-Gigahertz processors are, doesn't it? Look over at your computer - by the time the light from it reaches your eyes, it's probably already working on it's next instruction.

but our brain (our sight) looks ahead, meaning that if a car is driving by and we want to trace it with our eyes, we do not look at where it was a second ago, we look at where it will be at the time when the light will hit the retina and our brain will process the information - sort of looking ahead, based on the pattern/speed/direction of its movement.

You're not dealing with the lightspeed delay there, though; the time taken for the light to travel from car to retina is totally insignificant. You're comp

yup. and if you realize that the source of the explosion was an interstellar spaceship accellerating to lightspeed, then you know that it's going to start braking near this solar system any minute now.

Weeeelll, if it happened 440 million LY ago, and it takes that long for it to get to us, we can't tell what happened after that since it hasn't gotten "here" yet. So it's not that "do we care about that", but it's "we can't check on anything that happened after that till it gets here".

Then there's timing. Red shifting would cause the duration of an emission to expand as well. If most GRBs, after traveling billions of years, only last a few seconds then the event which caused the emission must be on the order of a few milliseconds (or arbitrarily "less than a few seconds"). This burst was 440 million years off and lasted 33 minutes. The amount of red shifting would be significantly less between 440 million years and several billion... so the originating event could still have been on the

That started as a joke, but now I really want to know: Why DO we care?

Why do we care about most things in the news -- hardly any affect us personally or directly. If you insist on a practical application; this is a sign of a massive explosion, a gigantic energy release. If we survive, we will need to know how to do things like that in a few million years -- they'd be ultimate WMDs, sterilizing an entire galaxy, or more hopefully have a constructive use.

This is a good exercise in drawing distinctions between cows and humans. Upon seeing a large explosion several miles away, a cow would likely blink, lower its head, and continue to munch grass. The explosion would not immediately affect the cow's practical agenda, which is to eat.

Most humans, and perhaps some higher mammals, would be curious as to the nature, cause, and ultimate ramifications of the explosion. Most of us would like to investigate it. Perhaps the explosion is related to other, smaller

Does this mean the event happened 440 million years ago and we're just now detecting it because information about it has finally arrived?

Assuming the explosion site is moving only slowly relative to us, which it almost certainly is - then yep, that's exactly what it means. If we're in rapid motion relative to each other then things get a little more complicated, because the meaning of the word 'ago' gets rather blurred...

Right, but how far apart were we when it happened, and how far apart are we now? If we were closer, then it happened more recently. If we were further, then it happened longer ago... Granted, we ought to be moving apart, like "everything" around here, but this is a freak occurrence anyway.

This is Brigadier Kerla speaking for the High Command. There has been an incident on Praxis. However, everything is under control, we have no need for assistance. Obey treaty stipulations and remain outside the Neutral Zone. This transmission ends now.

Within the last few months, there was a nice supernova (SN2005cs [rochesterastronomy.org]) in the Whirlpool Galaxy (spiral galaxy M51) which was quite visible at night using typical amateur reflecting telescopes of 16 or fewer inches aperture - in fact, it was discovered by an amateur! - hardly requiring anything near the size of Keck.:)

Keck and the other scopes on Mauna Kea will, though, sometimes try to sneak a peek at a "high-priority" target like this, if they can find the time in their busy schedules.

Ignoring all the silly posts above, this is a fascinating event. It's nice to know there's still mystery in the universe, and the prospect of seeing a supernova unfold is very exciting. I'm not sure, but I believe a supernova would outshine any other stars in the sky, even from that distance (although this may only be stars within out galaxy). Either way, it will let us get valuable information on the hardest part of a star's life to observe: their death.

So they say *most* are billions of light years away and happen for just seconds. Have they ever thought perhaps their measurements of space/time are not correct, and while those other bursts they've seen may really be billions of light years away, they could actually be happening for hours? If nothing else, I would be more interested in the previous findings and how space time may actually behave differently over greater distances than previously thought. IANAS though, so perhaps it's just the wandering

It appears to be a Type Ib/c supernova --
meaning a massive star, which has lost most
of its hydrogen envelope, running out of
fuel in its core and exploding -- in a
relatively nearby galaxy. By "nearby",
I mean "at a redshift of z=0.033",
which is still much farther away than
the Virgo or Coma clusters of galaxies.

It is currently around magnitude 18, and may
brighten by a magnitude or so, but will still
require a pretty big telescope and sensitive
camera to detect.

A very big telescope in Chile (GMOS) took an image of the object and recorded it's spectrum (light broken down by wavelength and recorded). From the spectrum, there is continuum radiation than has intensity proportional to the wavelength raised to some power. However, there are also features (spectral lines) in the spectrum which suggest it is a Type Ib or Ic supernova (exploding star).

It appears to be a Type Ib/c supernova -- meaning a massive star, which has lost most of its hydrogen envelope, running out of fuel in its core and exploding -- in a relatively nearby galaxy. By "nearby", I mean "at a redshift of z=0.033", which is still much farther away than the Virgo or Coma clusters of galaxies.

Supernovae like these occur due to the collapse of the core of a star as there is not enough fuel to sustain fusion to keep the star from collapsing under it's own gravity. The implosion creates a massive amount of heat which causes the explosion we see. Different to the proposed mechanism for a Ia Supernova.

It's actually pretty close (in universe terms). (Still a damn long way away!) The redshift (z) is defined at wikipedia [wikipedia.org]. The Virgo and Coma clusters are large nearby galaxy clusters.

It is currently around magnitude 18, and may brighten by a magnitude or so, but will still require a pretty big telescope and sensitive camera to detect.

Each decrease in magnitude is 100^1/5 times brighter than the previous one (it's a little confusing). A magnitude 0 star is about 2.5 times brighter than a magnitude 1 which is 2.5times brighter than magnitude 2, and so on. The brightest star in the sky (Sirius - visible tonight) is magnitude -1.6 (negatives are fine). The dimmest star you'll see with unaided eyesight is about 6 in really good dark skies, about 2 or 3 from a city. The Sun is -26.7, the moon about -13. This object is about 60000 times dimmer than a magnitude 6 star. (100^(12/5)).

Amateur telescopes with ccd cameras should be able to record this. It'd be pretty much impossible to actually see with the human eye and a telescope.

In brief, a star went bang; it's the first time we've been able to see it this early in the explosion; it's fairly close (but not too close); Don't bother to try to look for it in binoculars.

Obviously, it was a malfunctioning StarDrive, a magnetic containment breach, which allowed the escape of Gamma particles for approximately 33 minutes, until the engineering crew was able to get the containment field to stabililze and stop the leak.

Until we discovered that gamma ray bursts are not uniformly distributed, they appeared to defy E=MC^2; were they to radiate uniformly, E=MC^2 would suggest impossibly massive sources. Instead, as we understand them right now, they radiate much like a spotlight and cannot be directly measured beyond the penumbraThis article suggests that this gamma ray burst may simply be from a different angle than the continuous bombardments of gamma ray bursts that we have been studying since the beginning of the cold war

I'm going for "how little we understand the universe". All our theories are nice and tidy, but none of them really predict the organized chaos of the universe. They only describe what is possible, probably, or unlikely. Thus every once in a while we come across something that we didn't expect, or (even better) we come across something our current theories can't explain. (Which then results in a greater understanding of the universe, and an update to our theories.):-)